Field of the Invention
The present invention relates in general to computers, and more particularly to method embodiments for saving log data in a hierarchical storage management (HSM) system using a disk system as a primary cache with a tape library as a secondary cache in a computing storage environment.
Description of the Related Art
Log data generated from microcodes of a hierarchical storage management (HSM) system, typified by a virtual tape server (VTS) or the like, is stored in a hard disk which is the system's primary cache. The primary cache, however, is generally limited in storage area in comparison with the secondary cache. Therefore, the amount of log data which can be left is limited, and usually the old log data is overwritten as new log data is logged or written into storage. In addition, such log data is less important than user data, or other data, and therefore it is difficult to secure a large size for the primary cache as a storage area for logging. However, if a problem occurs at a customer's office, the problem analysis is performed on the basis of the logged data that is stored and any extremely old log data may be necessary for proper analysis to solve the particular problem. Older logged data, however, often times is lost after overwriting (wrapping) with newer logged data, making it difficult to perform the problem analysis.